Wastewater collection began in Lynn in 1866 with the construction of a stone and brick sewer in Union street. By 1879, the Lynn City Engineer reported that all but 7.5 miles of major streets had been sewered. In the 1880's and early 1890's, many of the larger sewer mains were constructed including the Eastern and Western Interceptors along with several of the submains. During that decade, the number of connections rose from 1,005 to 1,988. The system has continued to expand and there are 140 miles of pipe.
The Eastern interceptor is approximately 1,000 feet long and ranges in size from 40 inches by 54 inches to 64 inches by 72 inches. It is an egg shaped brick sewer constructed in 1885-1887. The Eastern Interceptor has not needed major renovation. A section of the interceptor was built in 1979 when the primary treatment plant was being built.
The Western interceptor is approximately 10,400 feet long and ranges in size from 36 inches in diameter to 54 inches by 72 inches. It is egg shaped in some sections and circular in others, and was constructed in 1890-1891.